Free vs. Available Memory in Linux

[hydn (Hayden James)]

Hi @randUser. Welcome to the community!

@randUser

Free is memory that has not been used in the current session. Where as available is memory that is being used as cache and buffers but can be freed at will for new or existing processes to use. Is this correct?

Yes.

Also, great questions! Here’s a brief explanation:

1. Free memory is what’s completely unused right now. Available memory includes both free memory and memory currently used by cache and buffers, which can be freed up instantly for new processes.
2. Free shows unused memory, while Available gives a more accurate picture of the available memory your system can use if needed.
3. Memory used for cache and buffers is low-priority. The system can quickly free it up for new processes without affecting running applications which are high-priority.
4. Free memory is unused and just sits idle. Linux optimizes performance by using as much memory as possible for caching. If a large portion of your memory is always free, you might have more RAM than needed. Ideally, your system should use around 80% or more of available memory for all your tasks, rather than having a significant amount, like 16 GB out of 32 GB, sitting unused (Free).

Hope this helps!